This is a continuation-in-part of copending International Application PCT/EP03/00309 having an international filing date of 14 Jan. 2003.
The underlying invention generally relates to the field of mobile computing in a wireless mobile networking environment with distributed multimedia applications and technologies. More specifically, it is directed to the field of Quality-of-Service (QoS) management for adaptive real-time services running on mobile devices which support different access technologies in dynamic wireless Internet Protocol (IP) networks, thereby including research and development issues which are especially related to multimedia middleware and resource reservation mechanisms. In this context, the invention proposes a model for defining user profile and terminal capability information in such a way that hierarchical QoS contract specifications (e.g. compelling correlations across different sets of QoS contracts for related media streams) can be enforced and used for deriving negotiable information.
As a reference implementation of this concept, this invention proposes a novel usage of the Session Initiation Protocol (SIP) standardized by the Internet Engineering Task Force (IETF) in conjunction with extensions of the Session Description Protocol Next Generation (SDPng) specification based on the Extensible Markup Language (XML) in order to implement End-to-End QoS Negotiation Protocol (E2ENP) concepts. The concept of the proposed solution according to the underlying invention is based on a proposal which has originally been identified in “Concepts for Service Adaptation, Scalability and QoS Handling on Mobility-Enabled Networks” (IST1999-10050 BRAIN Deliverable 1.2, Mar. 31, 2001, http://www.ist-brain.org/), in the following referred to as [BRAIN], along with a specific reference architecture. In this context, a set of basic requirements shall be derived. Thereby, a discussion shall be opened concerning this set of requirements and the choice of an optimal solution with regard to said requirements.
The Internet has proven to be a successful architecture for delivering a broad set of electronic services (including—among many others—telephony, electronic messaging, and audio/video services), not only to sedentary but also to nomadic users. Micro and macro IP mobility and wireless IP technologies in fact pave the way to the full integration of the Internet with the second and third generation of mobile phone systems. In order to achieve this object, next generation IP networks and applications will have to address the increasingly important challenges of wireless access, mobility management, the provision of Quality of Service (QoS), and multimedia services.
A paramount problem that mobile users will most likely face within this context is how to cope with limited amount resources at the end systems and in the network, and unstable environment conditions. Mobile users are in fact expected to incur more frequently on the unfortunate case of haying their QoS contracts being no longer supported by the network infrastructure, due to various reasons like: wireless link quality degradations, horizontal and/or vertical-handovers, limited amount of mobile terminal resources. In the rest of this document, these unfortunate cases shall be referred to as “QoS violations”. By assuming proper resource overprovision in the backbone, it can be expected that QoS violations will most likely originate in the access network, especially in the radio part thereof.
Furthermore, mobile multimedia applications dealing with multiple media streams of information being exchanged simultaneously with a multiplicity of peers will require an effective and efficient way of handling QoS requirements, especially in front of the aforementioned unstable environment conditions.
A possible way of coping with unstable environment conditions is to enable the mobile users' applications to efficiently and timely react to QoS violations, by planning counteractions ahead. Peers can in fact negotiate off-line various alternative QoS contracts at different levels of abstraction, so that at connection establishment time and whenever QoS violations occur, agreements on how to most effectively adapt to the mutated conditions can be timely reached among the peers.
Furthermore, peers can follow a specific procedure for effectively enforcing the pre-negotiated QoS contracts, by avoiding to request any network resource reservation before local resources at all the involved peers have been determined and reservations thereof have been accordingly made. This procedure is further addressed as “Economy Principle”.
The overall solution combining the above-mentioned two planning mechanisms shall now be called “End-to-End Negotiation Protocol” (E2ENP).
In particular, it should be noted that the negotiation of capabilities (e.g. codecs) is hereby regarded as a separate issue, complementary to the negotiation of user's QoS preferences and profile information. Intelligent, adaptive applications and/or middleware can thus make effective use of any such information negotiated end-to-end by the peers in order to choose the best adaptation strategy in reaction to a given QoS violation as described in [BRAIN].